The understandable principle from the WCAG describes how elements of the user interface should be understandable to the users. In this case, it should be understandable and clear from the content, design, and action point of view – whether the application is used with or without assistive technology.
This principle is divided into three main aspects: readable, predictable, and input assistance.
This aspect of understandable principle is defined as:
Make text content readable and understandable.
-- WCAG 2.1
Based on that, the application content should be identifiable by the language used in the application. Content and all words mentioned in the application should have a context while avoiding unusual words, abbreviations, and jargon.
The predictable aspect of this principle says:
Make Web pages appear and operate in predictable ways.
-- WCAG 2.1
This is initially defined for web pages but is also applicable for mobile applications (pages or screens). The idea is to have a consistent design and application behavior to make users comfortable using the application.
The context in which the user operates should be logical, without problematic behavior, which would lead to inconsistent navigation, component identification, or context switching.
One of the most important parts of the application is user input, and as a developer, you should provide the best experience for operations that involves user input.
Input assistance is defined as:
Help users avoid and correct mistakes
-- WCAG 2.1
We should provide enough information to the user when input elements are used inside the application, like labels, placeholders, or instructions. The same goes for error identification and appearance, which should provide enough information and context of the input state. With a good approach, users will be able to use input elements with ease, whether they use them with or without assistive technologies.
In this chapter, you can find principle-related guidelines and examples for mobile platforms:
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